Jet pumps are previously known for the propulsion of high-speed watercraft. In one type of installation, the hull of the watercraft is provided with an inlet aperture through the bottom of the hull adjacent to the transom. An axial or centrifugal pump takes suction through the inlet and discharges the water to a pressure chamber. The pressure chamber outlets an airborne jet of water. The resulting reactive force provides propulsion to the high-speed boat. Deflectors are typically mounted to the jet pump and are used to change the direction of the airborne jet of water thus altering the reactive force of the jet to steer the boat. Deflectors are commonly used to redirect the jet of water in a forward direction allowing the boat to back up. See, for example, the following U.S. Pat. Nos. 7,220,154; 4,073,257; and 3,336,752; the disclosures of which are incorporated by reference.
It is also known to provide jet pumps to outboard motors. Typically, a pump inlet is provided at the bottom of the motor adjacent to the surface of the water. The inlet communicates to an axial or centrifugal pump which discharges to an outboard motor-mounted pressure chamber. The pressure chamber discharges an airborne water jet at an outlet of a outboard motor. The reactive force acting on the outboard is commonly used to propel a small watercraft, typically at high speeds or in shallow water conditions. See, for example, the following U.S. Pat. Nos. 4,538,996; 4,281,996; and 3,105,353; the disclosures of which are incorporated by reference.
In my U.S. Pat. No. 4,645,463 entitled Marine Outdrive Apparatus, I disclosed marine outdrive attached to the transom of a boat having an inboard engine. The marine outdrive includes a tubular support casing securable to and extendable rearwardly of the boat's transom and having a ball socket at its rear end. The ball socket receives a ball at the front end of a tubular, propeller shaft carrier. A drive shaft connectable to the inboard engine is journaled in the support casing. A propeller shaft is journaled in the propeller shaft carrier and has a propeller mounted thereon at the rear end of the propeller shaft carrier. The propeller shaft transmits thrust to the ball at a conical thrust bearing. A double Cardan joint—sometimes called a universal joint—couples the two shafts together to transmit torque between the shafts, the center of such joint substantially coinciding with the point about which the ball pivots within the ball socket. Hydraulic steering cylinders are attached to the propeller shaft carrier to pivot the latter about a steering axis extending through the pivot point of the ball. A hydraulic trim cylinder extends between the transom and the propeller shaft carrier to swing the propeller shaft carrier about a laterally extending trim axis extending through the pivot point of the ball. The upper end of the trim cylinder is pivotally mounted on the transom at a location above and vertically aligned with the pivot point of the ball or at a location above and forwardly of such pivot point. Improved fins are provided on the propeller shaft carrier near the propeller to stabilize the boat. The drive shaft of the inboard motor can be directly connected to the joint or offset from the joint and coupled thereto by a vertically extending transmission.